An Abuse-Free Optimistic Signature Exchange Protocol Using Block Cipher

Digital Signature plays a vital role in secure business transactions and e-commerce applications. There are many existing schemes for secure exchange of digital signature over the network, but the problem arises when both the parties involved in the transaction do not trust each other. We have proposed a partial signature exchange scheme that is not only fair and optimistic also abuse free. Most of the existing protocols uses RSA multisignature. In the proposed protocol we use a block cipher technique to compute partial signatures which is computationally simple than the RSA signature schemes. Moreover our protocol supports verifiability by comparing partial signatures received. The involvement of TTP is also reduced. The proposed protocol can also be extended for multiple TTP´s and different characters which assures more security.